Influence of extraction methods on the yield of essential oil and phenolic composition of rosemary extract (Rosmarinus officinalis L.)

Cilj ovog rada bio je odrediti udio eteričnog ulja i fenolni sastav ekstrakta lista ružmarina nakon vodene destilacije po Clavengeru. Vodenoj destilaciji po Clavengeru prethodili su predtretmani: ekstrakcija refluksiranjem, ekstrakcija refluksiranjem potpomognuta enzimima te ultrazvučna ekstrakcija s ili bez dodatka enzima. Uz eterično ulje dobiveni su nusprodukti (vodeni ekstrakt i hidrolat) koji u svom sastavu sadrže fenolne spojeve. Biljni ostaci podvrgnuti su ekstrakciji potpomognutoj ultrazvukom primjenom otapala različite polarnosti (etanol-voda (1:1), metanol-voda (1:1) i etanol-metanol-voda (1:1:1)). Najveći udio eteričnog ulja (1 mL/100 g) dobiven je uz predtretman ekstrakcije potpomognute ultrazvukom i dodatak enzima ksilanaze. Najveći maseni udio ukupnih fenolnih spojeva određen je u vodenim ekstraktima ružmarina (44,02 ± 5,38 mg GAE g-1), dok je najveći udio ukupnih fenolnih spojeva u hidrolatu (0,2 mg GAE g-1) određen ekstrakcijom potpomognutom ultrazvukom. Pri ekstrakciji fenolnih spojeva iz biljnog ostatka važan je izbor otapala te primijenjeni predtretmani, a najveći prinosi fenolnih spojeva dobivaju se primjenom otapala etanol-voda (1:1) i prethodnim tretmanom enzimom ksilanazom.The aim of this study was to determine the yield of essential oil and phenolic composition of rosemary leaves extract after Clavenger hydro-distillation. Clavenger hydro-distillation was preceded by refluxing or ultrasound-assisted extraction with or without the addition of an enzyme. By-products (aqueous extract and hydrolate) containe phenolic compounds in their composition. Plant residues were subjected to ultrasound-assisted extraction using solvents of different polarity (ethanol-water (1:1), methanol-water (1:1) and ethanol-methanol-water (1:1:1)). The highest yield of essential oil (1 mL/100g) was obtained by ultrasound pre-treatment and addition of xylanase enzyme. The highest mass fraction of total phenolic compounds in aqueous extracts (44,02 ± 5,38 mg GAE g-1) was obtained by refluxing, while the highest fraction of total phenolic compounds in the hydrolate (0,2 mg GAE g-1) was obtained with ultrasound-assisted extraction. In the extraction of phenolic compounds the choice of solvent and the applied pretreatments are shown to be important factors. The highest proportion of phenolic compounds was extracted using the ethanol-water solvent (1:1) and the xylanase enzyme